1. Field of the Invention
Spinnerets with very small capillaries made from corrosion resistant materials have long been sought by producers of some fiber products. For example, aramids (such as poly(p-phenylene terephthalamide)) are often spun from hot concentrated sulfuric acid solution and require spinnerets of corrosion resistant material.
2. Description of the Prior Art
U.S. Pat. No. 4,054,468 (Honnaker et al.) discloses a corrosion-resistant spinneret and a process for making such a spinneret by forming and machining a laminate comprising a support body of stainless steel or tantalum alloy and a face layer of pure tantalum metal which has been explosively bonded to the support body. The process requires machining of the support body of the spinneret blank, drilling counterbores through the support body and partially into the face layer, forming spinneret capillaries from the counterbores through the face layer to the exit face of the spinneret, polishing the face to remove protrusions, and hardening the face by heat-treatment in nitrogen. The spinnerets of that patent require two-layer materials.